Chemical modification of lysozyme, glucose 6-phosphate dehydrogenase, and bovine eye lens proteins induced by peroxyl radicals: role of oxidizable amino acid residues
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Chemical modification of lysozyme, glucose 6-phosphate dehydrogenase, and bovine eye lens proteins induced by peroxyl radicals : role of oxidizable amino acid residues. / Arenas, Andrea; López-Alarcón, Camilo; Kogan, Marcelo; Lissi, Eduardo; Davies, Michael Jonathan; Silva, Eduardo.
In: Chemical Research in Toxicology, Vol. 26, No. 1, 18.01.2013, p. 67-77.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Chemical modification of lysozyme, glucose 6-phosphate dehydrogenase, and bovine eye lens proteins induced by peroxyl radicals
T2 - role of oxidizable amino acid residues
AU - Arenas, Andrea
AU - López-Alarcón, Camilo
AU - Kogan, Marcelo
AU - Lissi, Eduardo
AU - Davies, Michael Jonathan
AU - Silva, Eduardo
PY - 2013/1/18
Y1 - 2013/1/18
N2 - Chemical and structural alterations to lysozyme (LYSO), glucose 6-phosphate dehydrogenase (G6PD), and bovine eye lens proteins (BLP) promoted by peroxyl radicals generated by the thermal decomposition of 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) under aerobic conditions were investigated. SDS-PAGE analysis of the AAPH-treated proteins revealed the occurrence of protein aggregation, cross-linking, and fragmentation; BLP, which are naturally organized in globular assemblies, were the most affected proteins. Transmission electron microscopy (TEM) analysis of BLP shows the formation of complex protein aggregates after treatment with AAPH. These structural modifications were accompanied by the formation of protein carbonyl groups and protein hydroperoxides. The yield of carbonyls was lower than that for protein hydroperoxide generation and was unrelated to protein fragmentation. The oxidized proteins were also characterized by significant oxidation of Met, Trp, and Tyr (but not other) residues, and low levels of dityrosine. As the dityrosine yield is too low to account for the observed cross-linking, we propose that aggregation is associated with tryptophan oxidation and Trp-derived cross-links. It is also proposed that Trp oxidation products play a fundamental role in nonrandom fragmentation and carbonyl group formation particularly for LYSO and G6PD. These data point to a complex mechanism of peroxyl-radical mediated modification of proteins with monomeric (LYSO), dimeric (G6PD), and multimeric (BLP) structural organization, which not only results in oxidation of protein side chains but also gives rise to radical-mediated protein cross-links and fragmentation, with Trp species being critical intermediates.
AB - Chemical and structural alterations to lysozyme (LYSO), glucose 6-phosphate dehydrogenase (G6PD), and bovine eye lens proteins (BLP) promoted by peroxyl radicals generated by the thermal decomposition of 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) under aerobic conditions were investigated. SDS-PAGE analysis of the AAPH-treated proteins revealed the occurrence of protein aggregation, cross-linking, and fragmentation; BLP, which are naturally organized in globular assemblies, were the most affected proteins. Transmission electron microscopy (TEM) analysis of BLP shows the formation of complex protein aggregates after treatment with AAPH. These structural modifications were accompanied by the formation of protein carbonyl groups and protein hydroperoxides. The yield of carbonyls was lower than that for protein hydroperoxide generation and was unrelated to protein fragmentation. The oxidized proteins were also characterized by significant oxidation of Met, Trp, and Tyr (but not other) residues, and low levels of dityrosine. As the dityrosine yield is too low to account for the observed cross-linking, we propose that aggregation is associated with tryptophan oxidation and Trp-derived cross-links. It is also proposed that Trp oxidation products play a fundamental role in nonrandom fragmentation and carbonyl group formation particularly for LYSO and G6PD. These data point to a complex mechanism of peroxyl-radical mediated modification of proteins with monomeric (LYSO), dimeric (G6PD), and multimeric (BLP) structural organization, which not only results in oxidation of protein side chains but also gives rise to radical-mediated protein cross-links and fragmentation, with Trp species being critical intermediates.
KW - Amidines
KW - Amino Acids
KW - Animals
KW - Cattle
KW - Crystallins
KW - Dimerization
KW - Electrophoresis, Polyacrylamide Gel
KW - Glucosephosphate Dehydrogenase
KW - Hydrogen Peroxide
KW - Muramidase
KW - Oxidation-Reduction
KW - Peroxides
KW - Protein Carbonylation
KW - Spectrophotometry
KW - Tyrosine
U2 - 10.1021/tx300372t
DO - 10.1021/tx300372t
M3 - Journal article
C2 - 23252580
VL - 26
SP - 67
EP - 77
JO - Chemical Research in Toxicology
JF - Chemical Research in Toxicology
SN - 0893-228X
IS - 1
ER -
ID: 128974507